Vacant television frequencies, often referred to as TV white spaces, have been allowed for use on an unlicensed basis in many geographical areas. These TV white spaces are frequency channels allocated for television broadcasting that will not be used in given geographic areas. Many proposals exist for using the TV white space (TVWS) spectrum. For example, it has been suggested that wireless regional area networks (WRANs) could be established to provide high-speed internet access with a larger coverage. Also application of wireless local area networks (WLANs) on TV white spaces is planned.
Currently the basic rules of the Federal Communications Commission (FCC) for TVWS operations in the US on secondary basis specify that a network can be initiated by a Mode II personal/portable or a Fixed device that accesses a database to check available channels based on the geographical location of the device. Such devices may be referred generally as master devices. The master device can initiate a network in an available channel and it can provide the list of available channels for client devices. A client device is a device that cannot initiate a network but operates under control of a master device. The IEEE 802.19 task group 1 has started to define a coexistence management system to facilitate coexistence among different kind of networks and devices in TVWS.